To immobilize a boat along a quay or pontoon, ropes are used that are sufficiently robust and, if possible, elastic enough, which are called mooring lines.
There are three types of mooring lines:
a) Head and Aft lines :
- The Bow line is fixed at the bow and goes ashore further forward.
- The Stern line is fixed the stern and goes ashore further back.
b) Springs :
- The Bow spring: goes ashore further back than its anchor point on the boat.
- The Stern spring: goes ashore further forward than its anchor point on the boat.
c) Breast lines : ( Bow or Stern) are sometimes placed perpendicular to the centreline of the vessel and are essentially used to prevent the vessel from moving away from the dock.
An efficient and balanced mooring system generally requires at least four mooring lines, arranged symmetrically as much as possible (depending on the mooring points available on land). The aim is to prevent the boat from moving forward or backward and to keep it parallel to the quay, so that a few cleverly placed fenders are enough to protect it.
For a short-time mooring, with a small boat in a sheltered harbour, without appreciable variations in water level, it is sometimes sufficient to simply use a bow and a stern line, provided that the two mooring lines form an angle of about 45° to the longitudinal axis of the boat. In this way, the three conditions will be met: the boat will not be able to move forward, backward or stray from the quay. However, the use of at least 4 mooring lines is still recommended.
If the mooring area is exposed to waves or water level variations, it is important that the boat is not too blocked in its movements, as the mooring lines or cleats may break. In this case, it is necessary to provide longer bow and stern lines and springs, adding, if possible, shock absorbers to be placed on the mooring lines. The number of fenders will also have to be increased.
